Read the Docs explains its June DDoS attack
Read the Docs absorbed over 5.5 million requests per minute for nearly ten days—about 100× its normal peak—from a globally distributed attack that randomized headers and TLS parameters and deliberately targeted uncached 404 and 302 paths.
The practical defense was layered: aggressive edge caching, targeted rate limits and challenges, fingerprint/ASN rules, and Terraform-managed Cloudflare policy. The team avoided a blanket JavaScript challenge so APIs and ordinary readers kept working. HN discussion focused on the cache-miss attack surface, the economics of autoscaling, and whether this looked like an adaptive scraper; the author says it was deliberately designed to cause outages and cost.